diff --git a/mozilla/allmakefiles.sh b/mozilla/allmakefiles.sh
index 2cfee05f617..d128425e940 100755
--- a/mozilla/allmakefiles.sh
+++ b/mozilla/allmakefiles.sh
@@ -1005,6 +1005,11 @@ if [ "$NS_TRACE_MALLOC" ]; then
     MAKEFILES_tracemalloc="tools/trace-malloc/Makefile"
 fi
 
+# tools/codesighs
+if [ "$MOZ_MAPINFO" ]; then
+    MAKEFILES_codesighs="tools/codesighs/Makefile"
+fi
+
 # MathML
 if [ "$MOZ_MATHML" ]; then
     MAKEFILES_intl="$MAKEFILES_intl
@@ -1201,6 +1206,7 @@ $MAKEFILES_dbm
 $MAKEFILES_docshell
 $MAKEFILES_dom
 $MAKEFILES_editor
+$MAKEFILES_codesighs
 $MAKEFILES_composer
 $MAKEFILES_embedding
 $MAKEFILES_expat
diff --git a/mozilla/client.mk b/mozilla/client.mk
index 68d6563e20e..d11472b23dd 100644
--- a/mozilla/client.mk
+++ b/mozilla/client.mk
@@ -359,6 +359,19 @@ CHECKOUT_PHOENIX := true
 FASTUPDATE_PHOENIX := true
 endif
 
+####################################
+# CVS defines for codesighs (pulled and built if MOZ_MAPINFO is set)
+#
+CVSCO_CODESIGHS := $(CVSCO) $(CVS_CO_DATE_FLAGS) mozilla/tools/codesighs
+
+ifdef MOZ_MAPINFO
+FASTUPDATE_CODESIGHS := fast_update $(CVSCO_CODESIGHS)
+CHECKOUT_CODESIGHS := cvs_co $(CVSCO_CODESIGHS)
+else
+CHECKOUT_CODESIGHS := true
+FASTUPDATE_CODESIGHS := true
+endif
+
 #######################################################################
 # Rules
 # 
@@ -425,6 +438,7 @@ real_checkout:
 	$(CHECKOUT_CALENDAR) && \
 	$(CHECKOUT_LIBART) && \
 	$(CHECKOUT_PHOENIX) && \
+	$(CHECKOUT_CODESIGHS) && \
 	cvs_co $(CVSCO_SEAMONKEY) && \
 	cvs_co $(CVSCO_NOSUBDIRS)
 	@echo "checkout finish: "`date` | tee -a $(CVSCO_LOGFILE)
@@ -485,6 +499,7 @@ real_fast-update:
 	$(FASTUPDATE_CALENDAR) && \
 	$(FASTUPDATE_LIBART) && \
 	$(FASTUPDATE_PHOENIX) && \
+	$(FASTUPDATE_CODESIGHS) && \
 	fast_update $(CVSCO_SEAMONKEY) && \
 	fast_update $(CVSCO_NOSUBDIRS)
 	@echo "fast_update finish: "`date` | tee -a $(CVSCO_LOGFILE)